condition mean min max ZT0-3 8.157525 8.157525 8.157525 ZT4-7 7.2830200000000005 7.2830200000000005 7.2830200000000005 ZT8-11 7.943060000000001 7.943060000000001 7.943060000000001 ZT12-15 9.428625 9.428625 9.428625 ZT16-19 23.105600000000003 23.105600000000003 23.105600000000003 ZT20-23 10.36075 10.36075 10.36075